The aim of this study was to evaluate the sealing ability of conventional self-cured glass ionomer cement, silver glass ionomer cement and light-cured glass ionomer cement as retrofilling materials. Micro-leakage was assessed by introducing the samples into a 1 per cent solution of methylene blue for eight days at a constant temperature of 37 degrees C. Dye penetration was greater when silver glass ionomer cement was used in comparison to the other two materials tested; the difference was statistically significant. Conversely, the sealing ability of light-cured glass ionomer cement was significantly higher than that of conventional glass ionomer cement. The condition of the dentine-filling material interface and the marginal adaptation of the glass ionomer cements under study were assessed using scanning electron microscopy.